#define _CRT_SECURE_NO_WARNINGS 1

class Solution {
public:
    int peakIndexInMountainArray(vector<int>& arr)
    {
        int left = 0;
        int right = arr.size() - 1;
        int mid = 0;

        while (left < right)
        {
            mid = left + (right - left + 1) / 2;

            if (arr[mid] > arr[mid - 1])left = mid;
            if (arr[mid] < arr[mid - 1]) right = mid - 1;

        }

        return left;
    }
};